Which statement best characterizes Type III survivorship?

Which statement best characterizes Type III survivorship?

• A. The death rate is constant over the organism's life span
• B. The death rate declines after birth
• C. There is high survival of offspring to old age
• D. The greatest newborn mortality is experienced early in life

Answer: (D)

Type III survivorship curves describe life histories where a lot of offspring are produced but most die early, with only a small fraction making it to adulthood. This pattern means there is very high mortality right after birth, so the newborn stage is the riskiest. Those that do survive infancy then tend to have a much higher chance of living longer, leading to a long tail of survivors who reach older ages. This fits organisms like many fish, invertebrates, and plants that produce many offspring with little parental care. It’s different from a Type I pattern, where most individuals survive early life and mortality ramps up with age, and from a Type II pattern, where the risk of death is more constant across life. So the statement that greatest newborn mortality is experienced early in life best captures Type III.

Type III survivorship curves describe life histories where a lot of offspring are produced but most die early, with only a small fraction making it to adulthood. This pattern means there is very high mortality right after birth, so the newborn stage is the riskiest. Those that do survive infancy then tend to have a much higher chance of living longer, leading to a long tail of survivors who reach older ages. This fits organisms like many fish, invertebrates, and plants that produce many offspring with little parental care. It’s different from a Type I pattern, where most individuals survive early life and mortality ramps up with age, and from a Type II pattern, where the risk of death is more constant across life. So the statement that greatest newborn mortality is experienced early in life best captures Type III.